I am using a Linksys Wireless-G USB Network adapter in Ubuntu 9.10. I can connect with my wireless network when I am connected to the wired network. When I disconnect the ethernet cable, I lose the wireless connection also. Where is the best place to read about this problem? Thanks.

Hi.
Can you explain, what gives you a reason to think that when you disconnect ethernet cable you also lose wireless connection.

And actually, why do you think that when you are connected with ethernet you are also connected with wireless?

When the ethernet cable is connected it shows "wired Network" connected and "Wirless Network" connected. When I remove the ethernet cable the wired network is disconnected (as it should be). The wireless connection is still connected, but I can not go online. I plug the ethernet cable back in and I can go online.

To find out if you are really connected to wireless you need to type in root console:
And if in output you will see "ASSOCIATED" with your wireless AP - you are connected.

Check it, and check it as well without ethernet cable.

It looks as though Iam NOT connected through the wireless.

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wlan1 IEEE 802.11bg ESSID:"william"
Mode:Managed Frequency:2.412 GHz Access Point: 56:9E:51:35:25:AA
Bit Rate=54 Mb/s Tx-Power=7 dBm
RTS thr=2347 B Fragment thr=2346 B
Link Quality=60/100 Signal level=60/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

william@william-laptop:~$


After I unplug ethernet cable

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wlan1 IEEE 802.11bg ESSID:"william"
Mode:Managed Frequency:2.412 GHz Access Point: 56:9E:51:35:25:AA
Bit Rate=54 Mb/s Tx-Power=7 dBm
RTS thr=2347 B Fragment thr=2346 B
Link Quality=60/100 Signal level=60/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

Plug in ethernet cable and unplug wireless

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

After I unplug ethernet cable

william@william-laptop:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wlan1 IEEE 802.11bg ESSID:"william"
Mode:Managed Frequency:2.412 GHz Access Point: 56:9E:51:35:25:AA


You are connected with wireless - ESSID:"william" and Access Point: 56:9E:51:35:25:AA - it means that your computer is associated with AP "william"

Check first if you get an ip by typing ifconfig wlan1. If you have one, it may be a routing issue. Type netstat -nr and see if there is a default gateway trough your wireless interface wlan1.

In the other hand check why your iwconfig dont show your security setting. Type iwlist wlan1 encryption
iwlist wlan1 key

Thank you very much for helping.
Heres the results with the Ethernet cable disconnected wirless still connected:

william@william-laptop:~$ iwconfig wlan1

wlan1 IEEE 802.11bg ESSID:"william"

Mode:Managed Frequency:2.412 GHz Access Point: 96:1C:A6:92:CF:54

Bit Rate=54 Mb/s Tx-Power=7 dBm

RTS thr=2347 B Fragment thr=2346 B

Link Quality=60/100 Signal level=60/100

Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0

Tx excessive retries:0 Invalid misc:0 Missed beacon:0


william@william-laptop:~$ iwlist wlan1 encryption

wlan1 2 key sizes : 40, 104bits

4 keys available :

Error reading wireless keys (SIOCGIWENCODE): Operation not permitted


william@william-laptop:~$ iwlist wlan1 key

wlan1 2 key sizes : 40, 104bits

4 keys available :

Error reading wireless keys (SIOCGIWENCODE): Operation not permitted

Can you please while computer is connected by wireless type on root console:
Post, please output.

william@william-laptop:~$ route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.42.43.0 0.0.0.0 255.255.255.0 U 2 0 0 wlan1

Ok, thanks.
I would like to explain what is going on on your computer:
When you turn it on, network manager finds two interfaces: ethernet and wireless, and configures them.
It gives them IP addresses and brings them up, but those are not enough. One need to specifies a default route, and default interface, which it sets up to ethernet by DHCP client. Wired connection works, you can go to internet.
But when you disconnect ethernet, NM removes default router, but DHCP client doesn't start again because wireless already was configured.
So, you need to reconnect to wireless, after you unplug ethernet.
Try to turn wireless OFF and ON again, and tell if it helps.

I disconnected the wired connection and lost my internet connection. I then disconnected the wireless aand reconnected (i.e turned off then turned on again), but could not regain internet connection.
I tried rebooting with just the wirless reconnected and that don't work either.

I also tried rebooting the router with only the Wirless connection connected, but that doesn't work either.

I tried rebooting the router with the wireless connected and the wired connection disconnected, but that did not wok either.